May 24, 2014

There are many myths (widely held but false beliefs or ideas) about cicadas. Time to bust some cicada myths.

Myth 1: Cicadas are sleeping when they are underground.

There’s a popular meme that (mis)states the following “if cicadas can sleep for 17 years and then wake up only to scream and reproduce so can i”. The actual tweet doesn’t say “reproduce”, but I want to keep it clean.

American periodical cicadas aren’t sleeping the entire 17 years they’re underground. Much of the time they’re digging tunnels and building feeding cells, tapping into roots and feeding, vying with other cicadas for space along a crowded root system, growing (they experience four phases or instars while underground), avoiding unfavorable conditions like flooding, and possibly actively avoiding predators like moles and voles. Yes, cicadas can sleep — or at least the insect version of sleep called torpor — but they are definitely not asleep for 17 years.

That said cicadas do spend their time screaming (the males) and procreating once above ground.

Myth 2: All cicadas have a 17 year life cycle.

This is false. Only three species, out of the thousands of cicada species in the world, have a 17 year life cycle: Magicicada septendecim, Magicicada cassini, and Magicicada septendecula.

Myth 3: All cicadas have periodical life cycles and synchronized emergences.

This is false. Only seven species in the United States (belonging to the genus Magicicada), and a few species in Asia (belonging to the genus Chremistica 1) have been confirmed to have periodical life cycles and synchronized emergences.

All other species of cicadas emerge annually, although in some years they are more plentiful than in others.

Myth 4: All cicadas live a prime number of years.

Many cicadas live a prime number of years, but some do not. Chremistica ribhoi, the World Cup cicada, has four year life cycle.

Myth 5: A long, periodical, prime number life cycle has allowed American periodical cicadas to avoid gaining a predator.

American periodical cicadas have avoided gaining an animal predator that specifically predates them, but they haven’t avoided a fungus. Massospora cicadina is a fungal parasite of Magicicada cicadas.

That said, just about any animal will eat an American periodical cicada, so they definitely get eaten. They get eaten a lot.

It is true that some cicadas can make noise by stridulation, making sound by rubbing body parts.

However, and this is a huge however, the sound cicadas are known for is made by organs found in male cicadas called tymbals. Tymbals are a pair of ribbed membranes, that produce the cicada’s sound when they are flexed in and out by muscles. The mechanism is like the popping sound made when the plastic of a soda pop bottle is flexed in and out.

Cicadas can also make sound by flicking or clapping their wings.

Myth 7: Cicadas eat vegetation.

This is false. Cicadas lack the mouth parts to chew and swallow vegetable matter. Your tomatoes are safe around cicadas. Rather than eating solid food, cicadas ingest xylem, which is a type of tree sap that cicadas drink through their straw-like mouthparts.

Myth 8: American periodical cicadas are locusts.

Cicadas are not locusts. Locusts are a form of grasshopper. People confuse cicadas with locusts because both aggregate in massive numbers.

This is an image of a locust:

Characteristic

Locust

Cicada

Order

Orthoptera

Hemiptera

Hind Legs

Giant hind legs for jumping

Hind legs about the same size as other legs; great for climbing and perching.

What they eat

Everything green they can find to eat

Xylem sap

They’re in your town

All the plants in your town have been stripped bare

Cool UFO movie soundtrack sounds during the day

9) If you see a W appear in a cicada’s wings it means there will be a war. If you see a P, there will be peace.

This is the most mythical of cicada myths and has no basis in fact. That said, here’s the W:

Hello,
Thank you for this new post.
According to Michel Boulard, a periodical cicada (Abroma pumila) who lives in New Caledonia (Oceania) has a 3 year life cycle. (Boulard M., The Cicadas of Thailand, vol.1, p.65)